1. Field of the Invention
The present invention relates to a line image forming method and a line image forming apparatus, and more particularly to line image formation technology suitable for forming a line pattern on a surface of a non-permeable medium using an inkjet head.
2. Description of the Related Art
Japanese Patent Application Publication No. 2008-294308 discloses technology for forming a desired conductive pattern (circuit pattern) by applying a metallic nano-ink onto a polyimide film by inkjet printing. According to Japanese Patent Application Publication No. 2008-294308, by making the contact angle of the metallic nano-ink with respect to the polyimide film 10° or greater, bleeding of the metallic nano-ink after application is suppressed, and improvement in the accuracy of the pattern dimensions is achieved.
In Japanese Patent Application Publication No. 2008-294308, a metallic nano-ink droplet is dripped onto a polyimide varnish layer, the contact angle of the droplet on the surface is measured (paragraph 0034 in Japanese Patent Application Publication No. 2008-294308), and conditions relating to the static contact angle are stipulated. On the other hand, as shown in FIG. 9, it was confirmed in the experimentation performed by the present inventor that when carrying out straight line image formation by depositing droplets on a surface with an inkjet system and if the receding contact angle of the droplets on the surface was high, a line shape was not formed and an aggregate of dots was obtained.
Japanese Patent Application Publication No. 2008-294308 specifies the conditions relating to the static contact angle, but does not make any mention of the receding contact angle. Consequently, when image formation is carried out as described in Japanese Patent Application Publication No. 2008-294308, a satisfactory line shape is not obtained under certain conditions, resulting in a plurality of dots.